This invention pertains to electrical feedthrough penetrators and more particularly to those penetrators used in batteries requiring a sealed chamber.
There presently is being developed high performance batteries for powering electrical vehicles and for storing off-peak electrical energy generated by electric utility power stations. A typical battery is of the lithium-iron sulfide type. The electrolytes used in such batteries are molten and require operating temperatures of from 400.degree. to 500.degree. C. A typical electrolyte is a molten salt mixture of lithium chloride-potassium chloride (LiCl-K Cl). Such electrolytes create extremely hostile environments within batteries, especially at positive electrodes. Heretofore most electrical feedthrough penetrators to the batteries employed brazes for bonding ceramic insulators to metal conductors and housings. These brazes are not resistant to cell environment. The most common modes of failure are chemical oxidation of the brazes upon charging, reaction of the braze with the sulfides and galvanic corrosion at the braze joint resulting from the electrochemical dissimilarity of the braze materials from its adjacent parts.